1. Field of the Invention
This invention relates to a drive assembly for mechanized irrigation systems and more particularly to a flotation drive assembly for a mechanized irrigation system such as a corner pivot irrigation system, a center pivot irrigation system, or a linear move irrigation system. More particularly, this invention relates to a flotation drive assembly for mechanized irrigation systems which improves the field traction of the systems and which improves the resistance to wheel track rutting that may occur during the normal operation of the irrigation system. Even more particularly, this invention relates to a flotation drive assembly for mechanized irrigation systems wherein the gearboxes associated therewith do not support the weight of the system.
2. Description of the Related Art
Mechanized agricultural irrigation systems such as a corner pivot irrigation system, a center pivot irrigation system or a linear move irrigation system typically include a water delivery pipeline which is supported by a plurality of structural steel towers or drive units. The towers or drive units usually have at least two wheel/tire assemblies associated therewith which contact the ground and support a substantial percentage of the total weight of the system. The wheel/tire assemblies are usually mounted to a gearbox, which itself is mounted to the tower. The gearbox therefore experiences a significant overhung load due to the cantilevered arrangement of the wheel/tire assembly. When this setup is used with a wheel/tire assembly of a larger than average width, the overhung load becomes too large for current gearboxes to withstand and they eventually fail.
The need for a wider than normal traction contact patch arises from the significant rutting and traction problems that occur mainly in potato and sugar beet fields, however these problems do occur in other field situations as well. Past trials with gearbox arrangements using wider than average, or flotation, wheel/tire combinations have demonstrated large forces on the gearbox which have resulted in output shaft, flange, bearing and mounting failures. Such issues must be addressed before any flotation options may be utilized.